Rock-drill engine



(No Model.)

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Patented Jan. 25, 1898.

.mw w @my UNITED STATES nTnNT @erica GEORGE M. GITHENS, OF BROOKLYN, NEW YORK.

ROCK-DRILL ENGHNE.

SPECIFICATION forming part of Letters Patent No. 597,902, dated January 25, 1898.

Application filed July 21, 1897. Serial No. 645,358. (No model.)

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Be it known. that I, GEORGE M. GITHENs, a citizen of the United States, residi n g at Brooklyn, in the county of Kings and State of New Yorlnhave invented an Improvement in Rock- Drill Engines, of which the following is a speciiication.

In Let-ters Patent No. 247,819, granted to me October 4, 1881, a piston is represented having the middle portion of smaller diameter and an arc-shaped valve moved Erst in one direction and then in the other by the inclined surfaces at the ends of the smaller portion of the piston, and in Letters Patent No. 212,598, granted to me February 25, 1379, a similar piston and an arc valve are represented, there being` a rest at the concave side of the arc valve. l In rock-drilling engines I have experienced difticulty in consequence of the valve resting upon its seat andbeingheld there bythe pressure of air or steam and requiring considerable force to comm ence the movement of such valve, and the inclined surfaces of the piston coming into contact with the ends of such valve injure and wear the same in consequence of concussion, and the steam or air pressure is liable to accumulate and remain Within the cylinder around the smaller portion of the piston and exert its force in holding the valve to its seat.

The object of the present invention is to maintain an opening to the exhaust from the space Within the cylinder and around the smaller diameter of the piston, thus preventing an accnin ula-tion of pressure in this space and also to balance the steam or gaseous pressure in its action upon the valve, so that there will be but little tendency of the pressure to hold the valve to its seat, and the valve will therefore move with but little friction and Wear upon the valve and concussion by the parts of the piston striking the valve is reduced to a minimum.

In the drawings, Figure 1 is a section of the cylinder and valve-chest and valve. Fig. 2

is a cross-section at the line a: of Fig. 1. Fig. 3 is a plan view of the valve. Fig. 4 is an inverted plan view showing the face of the steam-chest, and Fig. 5 is a plan view of the cross-bearer detached.

The cylinder A is of any ordinary construction, and the piston B is provided with apiston-rod B', extending out ,through one end of the cylinder and receiving the drill or other tool to be actuated, and the cylinder-heads are to be of any desired character, and the middle portion of the piston VB is reduced, as shown at 3, there being inclined surfaces 4 and 5 for giving motion to the arc-shaped valve D, and this valve is against the face of valve seat 6 of the chest E'. This valvechest E is advantageously provided with the Screw-threaded holes 7 S 9 at one end for the recept-ion of the supplypipe for steam or other duid under pressure, such pipe being brought in Whatever is the most convenient direction to the chest, the other screw-threaded holes being closed by movable plugs and the fluid under pressure passes by the port 10, and there are ports 11 and 12 in the chest leading to thel ports 13 and la in the cylinder by which pressure reaches the ends of the cylinder to act upon the piston a's usual, and there are also in the chest ports 16 and 17 with branches at the ends opening into the cross-port 18 of the exhaust, the pipe for the exhaust being connected at either one side or the other of the chest E.

The arc valve D has a face that is the segment of a cylinder seating against the similar-shaped seatG of the valve-chest, and the valve-bearin g H is advantageously received at its ends in recesses in the cylinder,so that such bearing comes at each edge of the arc valve, and its inner surfaces are in line with the portion of the valve-chest that extends down into the recess of the cylinder, and there isa cross-piece 2O against the concave side of the arc valve, and these parts are litt-ed and advantageously ground so as to be steam-tight, but yet sufficiently loose to allo7 the valve to be moved end Wise Wi th freedom by the action of the inclines et and 5 of the piston B.

Inthe valve D there are ports 22 23 24, the port 24 being between the ports 22 and 23 and serving as a steam-port to connect the inletport 10 with the port 11 to one end ofthe cylinder or with the port 12 to the other end of the cylinder, and the ports 22 and 23 connect the port 11 with the exhaust 16 and the port 12 with the exhaust 17 so that when the valve is in the position shown in Fig. 1 the steam will pass by the port 13 to Withdraw the drill IOO or other tool, the exhaust from the opposite end of the cylinder passing by 14:, 12, 23, and 17' to the exhaust I8, and when the valve has been moved to the opposite position the exhaust will be from the other end of the cylinder through I3 Il 22 to 1G, and the steam will pass by 10, 24, 12, and 14 to project the drill or other tool.

The small holes 27 and 28, passing through the valve, are always open to the exhaust, so that an accumulation of pressure in the cylinder and around the reduced portion of the piston is prevented.

In the concave side of the valve is a counterbalance-port 30,0penin g to the port 24, and the size of this port 8O is nearly the same as the size of the port 24; and advantageously is slightly greater, and steam or air pressure is constantly acting both in 24 and 30 and in opposite directions, the pressure in 24 tending to force the valve against the cross-bar 2O and the pressure in 30 to force the valve against the seat. Hence these two forces can. be balanced, but the force acting to keep the valve upon its seat should slightly prepon derate.

By the aforesaid construction the valve is balanced so` that the pressure produces but little friction, and hence the valve can be moved upon its seat with great freedom and there is but little Wear to the parts.

The valve-bearing being a separate piece from the valve-chest allows for the easy and accurate fitting of the respective parts, and the bearing can be adjusted to bring the crossn bar to the proper proximity to the concave side of the valve, and the surfaces can be ground or dressed off, as may be necessary from time to time, thus insuring durability to the valve and its supporting parts.

The valve-bearing II is advantageously attached to the valve-chest by the screws O.

I do not limit myself to the location shown for the balancing-port, as this should always be opposite to the pressure to be balanced.

I claim as my invention- I. The combination with the cylinder and the reciprocating piston having a reduced central portion and inclined surfaces, of a valve-chest having supply and exhaust ports, an arc valve acted upon by the piston and a valve-bearing having a cross-bar at the concave side of the valve, such bearing being separate from the cylinder and from the valvechest, so as to be adjusted to the valve, substantially as set forth.

2. The valve-chest having inlet andexhaust pipe connections, and pressure and exhaust ports, in combination With an-arc valve havin gin its convex surface pressure and exhaust yports and an opening into the cylinder through such arc valve from one of the exhaust-ports, substantially as set forth.

3. In a reciprocating` engine for rocledrills or other devices, a piston having a reduced central portion with inclines, a valve-chest with an arc-shaped valve-seat, a valve acted upon by the inclines of the piston and a valvebearing having a cross-bar at the concave side of the valve and a port at the concave side of the valve for balancing the pressure, substantially as set forth.

4. The combination with the cylinder and piston having areduced central portion, ofa removable valve-chest having pressure and exhaust ports and connections for the pipes, an arc valve having three ports in its convex ,face and a port in its concave face, a crossbar at the concave side of the arc valve against which the balancing-pressure acts, substantially as set` forth.

The combination With the cylinder and `piston having a reduced central portion, of a removable valve-chest having pressure and exhaust ports and connections for the pipes, an are` valve having three ports in its convex face and a port in its concave face, a crossbar at the concave side of the arc valve against which the balancing-pressure acts, a valve-bearing connected with the cross-bar and separate from the valve-chest for adjusting the cross-bar to the valve, substantially as set forth.

6. The combination With the cylinder and piston having a reduced central portion, of a removable valve-chest having pressure and exhaust ports andconnections for the pipes, an are valve having three ports in its convex face and a port in its concave face, a crossbar at the concave side of the ,arc valve against Which the balancing-pressure acts, a valve-bearing connected With the cross-bar and separate from the valve-chest for adjusting the cross-bar to the valve, the valvebearing also extending at the edges of the valve and being Within recesses in the valvechest, substantially as set forth.

7. The combination in a reciprocating engine for rock-drills or other devices, of a piston having upon itinclines, a valve-chest with an arc-shaped valve-seat, a valve acted upon by the inclines and a port for balancing the pressure upon the arc valve, substantially as specified.

Signed by me this 19th day of July, 1897.

GEO. M. GITHENS.

Witnesses: CHAs. H. SMITH, S. T. HAVILAND.

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